"Civilization exists by geological consent"
(Will Durant (1885 - 1981), American historian, philosopher, and educator)
Not many people stop to think about the rock beneath their feet, but it is the type of rock, its structure and its history, together with climate, that determine the topography of the land and the type of soil. These, in turn, will determine what plants will grow and how much animal life the land will support.
Under the Bluegrass Region of Kentucky are layers of rock deposited over 400 million years ago, when this area was covered by a warm, shallow sea. Millions of years of uplift followed by many more millions of years of erosion have created Kentucky's Bluegrass landscape.
The Inner Bluegrass contains the oldest exposed rocks in Kentucky. As is common in areas with thick-bedded limestone formations and a humid climate, such as the Bluegrass, erosion has created a gently rolling landscape with numerous sinkholes, springs, and sinking streams. It is this landscape that typifies Kentucky's "horse farm country." The underlying rock in the Inner Bluegrass produces dark brown fertile soils with a high phosphate content. Animals that eat the grasses that grow on this soil, and that drink the water that percolates through it, develop light, very strong bones. It is this soil that makes the Bluegrass so suited to raising horses.
The bedrock of the Outer Bluegrass is somewhat younger. Many of the formations in this region contain interbedded shales and limestones. These formations are softer and more easily eroded. Here, the landscape is marked by steep hills and slopes, and flat land is at a premium.
The Ancient Kentucky
The Kentucky River is thought to be over 100 million years old, making it an extraordinarily old river. It begins in the mountains of Lee County, about 35 miles southeast of here. On its journey to the Ohio River, the Kentucky winds through the Inner and Outer Bluegrass Regions. From Frankfort to Boonesborough, located just across the river, the river cuts through thick limestone formations, creating steep walls known as the palisades.
Below Boonesborough, where the river cuts through softer rock, the valley widens and cliffsides, such as the one this trail climbs, border the river. Before 1800, dense forests covered the cliffsides. Most of this timber was cut in the 1800s by commercial logging concerns. This cliffside was cleared again in 1863 when the earthwork at the top of the trail was built. In all likelihood it was cleared once again before the present growth of trees developed.